Pioneer 1014TX-K - THX Select A/V Receiver, Service Manual

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VSX-52TX
116
1 2 3 4
1 2 3 4
C
D
F
A
B
E
7.1.2 HOW TO DIAGNOSE THE AMPLIFIER SECTION
When DC detection worked (STBY IND. flashes for a long time)
in the protection circuit of foregoing section (or there is not the
speaker output, probably only 1CH), failure (damage) of the
power amplifier section is considered.
Because this receiver cannot diagnose the amplifier section by an
electricity state by structure, please diagnose it in the following
steps.
Caution:
When release the STBY (flashes) state before repair, Because
there is the case that the damage progresses when turns the power
on once again, please be careful.
• According to a symptom, perform the following
confirmation beforehand.
1. Are not Fuse and IC protector opening it?
2-a. When can turn on electricity, confirm that supply voltage of
the point that can measure is appropriate.
2-b. Furthermore, confirm that voltage ((in a no signal) DC and
the appropriate signal output) between GND and R2008-
R2014 on the SP/PS Assy (Either of the amplifier side and
the speaker terminal side is possible) (Or remove either of
CN2101-2104) on the SP/PS Assy. And limit failure CH.
If was able to limit failure CH, diagnose the CH in the following
steps.
• Use the tester basically and check that each part is
not damaged (resistance value / open / short circuit).
About parts with damaged possibility, explain FL ch to an
example in order.
1. R4131, R4132 (ACN7132: 0.047
Ω
, 0.5W chip drain resistor)
IC 4102, IC4103 (PBD001A: Nch, PBD002A: Pch output
POWER MOS Tr.) /POWER AMP-L Assy
2. R4119 (ACN7121: 0.18
Ω
.5W
×
2 cement source resistor)
R4117, R4118 (RS1/16S471J: 470
Ω
chip resistor for
protection circuit)
D4101, D4103 (UDZS10B: 10V Zener diode for current
limiting)
D4102, D4104 (1SS355: Small signal diodes same as above)
R4110, R4111 (RS1/16S560J: 56
Ω
chip gate resistor)
R4106, R4107 (RS1/16S101J:100
Ω
chip IC4101 power filter
resistor) /POWER AMP-L Assy
3. IC4101 (PA9010A: Power amplifier with output current bias
Voltage step HIC) /POWER AMP-L Assy
4. Q2231 (2SA1514K) /VH TR Assy
Q2232 (2SC3906K) /VH TR Assy
Q2233 (2SA1837D1) /VH TR Assy
Q2234 (2SC4793D1) /VH TR Assy